Boost Weight Loss By Limiting Fructose

DALLAS – July 24, 2008 – One of the reasons people on low-carbohydrate diets may lose weight is that they reduce their intake of fructose, a type of sugar that can be made into body fat quickly, according to a researcher at UT Southwestern Medical Center.

Dr. Elizabeth Parks, associate professor of clinical nutrition and lead author of a study appearing in a current issue of the Journal of Nutrition, said her team's findings suggest that the right type of carbohydrates a person eats may be just as important in weight control as the number of calories a person eats.

Current health guidelines suggest that limiting processed carbohydrates, many of which contain high-fructose corn syrup, may help prevent weight gain, and the new data on fructose clearly support this recommendation.

"Our study shows for the first time the surprising speed with which humans make body fat from fructose," Dr. Parks said. Fructose, glucose and sucrose, which is a mixture of fructose and glucose, are all forms of sugar but are metabolized differently.

"All three can be made into triglycerides, a form of body fat; however, once you start the process of fat synthesis from fructose, it's hard to slow it down," she said.

In humans, triglycerides are predominantly formed in the liver, which acts like a traffic cop to coordinate the use of dietary sugars. It is the liver's job, when it encounters glucose, to decide whether the body needs to store the glucose as glycogen, burn it for energy or turn the glucose into triglycerides. When there's a lot of glucose to process, it is put aside to process later.

Fructose, on the other hand, enters this metabolic pathway downstream, bypassing the traffic cop and flooding the metabolic pathway.

"It's basically sneaking into the rock concert through the fence," Dr. Parks said. "It's a less-controlled movement of fructose through these pathways that causes it to contribute to greater triglyceride synthesis. The bottom line of this study is that fructose very quickly gets made into fat in the body."

Though fructose, a monosaccharide, or simple sugar, is naturally found in high levels in fruit, it is also added to many processed foods. Fructose is perhaps best known for its presence in the sweetener called high-fructose corn syrup or HFCS, which is typically 55 percent fructose and 45 percent glucose, similar to the mix that can be found in fruits. It has become the preferred sweetener for many food manufacturers because it is generally cheaper, sweeter and easier to blend into beverages than table sugar.

For the study, six healthy individuals performed three different tests in which they had to consume a fruit drink formulation. In one test, the breakfast drink was 100 percent glucose, similar to the liquid doctors give patients to test for diabetes – the oral glucose tolerance test. In the second test, they drank half glucose and half fructose, and in the third, they drank 25 percent glucose and 75 percent fructose. The tests were random and blinded, and the subjects ate a regular lunch about four hours later.

The researchers found that lipogenesis, the process by which sugars are turned into body fat, increased significantly when as little as half the glucose was replaced with fructose. Fructose given at breakfast also changed the way the body handled the food eaten at lunch. After fructose consumption, the liver increased the storage of lunch fats that might have been used for other purposes.

"The message from this study is powerful because body fat synthesis was measured immediately after the sweet drinks were consumed," Dr. Parks said. "The carbohydrates came into the body as sugars, the liver took the molecules apart like tinker toys, and put them back together to build fats. All this happened within four hours after the fructose drink. As a result, when the next meal was eaten, the lunch fat was more likely to be stored than burned.

"This is an underestimate of the effect of fructose because these individuals consumed the drinks while fasting and because the subjects were healthy, lean and could presumably process the fructose pretty quickly. Fat synthesis from sugars may be worse in people who are overweight or obese because this process may be already revved up."

Dr. Parks said that people trying to lose weight shouldn't eliminate fruit from their diets but that limiting processed foods containing the sugar may help.

"There are lots of people out there who want to demonize fructose as the cause of the obesity epidemic," she said. "I think it may be a contributor, but it's not the only problem. Americans are eating too many calories for their activity level. We're overeating fat, we're overeating protein; and we're overeating all sugars."

Contact: Kristen Holland Shear
kristen.hollandshear@utsouthwestern.edu
214-648-3404
UT Southwestern Medical Center

Tags: Weight Control, weight loss, fructose in body weight, clinical nutrition, fat synthesis from fructose, fat synthesis, glycogen, lipogenesis

Employer-Based Weight Loss Programs Are Helpful

CINCINNATI—A new review of studies from UC shows that a little shove from the workplace may actually be the ticket to dropping weight.

According to Michael Benedict, MD, and colleagues at UC, employer-based programs for weight loss are modestly effective at helping workers take off extra pounds.

“Worksite-based programs do tend to result in weight loss for the people that participate in them,” says Benedict, co-author of the study and researcher in the department of internal medicine.

The review appears in the July-August issue of the American Journal of Health Promotion.

Benedict and colleagues looked at 11 studies published since 1994 to determine their results.

Most of the programs involved education and counseling designed to improve diet and increase physical activity and lasted anywhere from two to 18 months. Forty-six percent of the studies involved low-intensity interventions, 18 percent were moderate intensity and 36 percent were high intensity.

Benedict says that intensity may be an important factor when it comes to weight loss. He added that programs incorporating face-to-face contact with subjects more than once a month appeared to be more effective than other programs.

In comparison, participants in higher intensity programs lost an average of 2.2 pounds to almost 14 pounds, while non-participants ranged from a loss of 1.5 pounds to a gain of 1.1 pounds.

“Most employed adults in the U.S. spend nearly half of their waking hours at their place of employment,” Benedict says. “Worksite based programs have great potential to positively impact our current obesity epidemic.

However, Benedict says it was difficult to draw conclusions about weight-loss maintenance.

“Participants in these programs may lose weight, but it is unclear what happens after the fact, as weight maintenance has not been studied,” he says.

There is also minimal data to show how much money employers could save if they start worksite weight-loss programs. Benedict says many employers want to know that implementing these programs will lead to a positive return on investment.

Studies have shown that other worksite health interventions targeting high risk employees, like smokers and people with hypertension, may benefit employers financially within only a few years.

“These programs have the potential to have a tremendous public health impact,” he says. “However, more high quality research is needed.”

Michael Benedict, MD,

Media Contact: Katie Pence, (513) 558-4561

Tags: weight loss, Weight Control, American Journal of Health Promotion

Does Your Weight Loss Programme Slow DOwn During Weekends?

June 30, 2008 -- Saturday can be the worst enemy for our waistlines, according to researchers at Washington University School of Medicine in St. Louis.
They found that study subjects on strict diet and exercise programs tend to lose weight more slowly than expected because they eat more on weekends than during the week. The investigators report their findings in the advance online publication of the journal Obesity.
Past research had confirmed that people tend to gain weight during the holidays, particularly between Thanksgiving and New Year's, but this is the first study to carefully monitor daily body weight, calorie intake and calorie expenditure for several weeks throughout a year, and to demonstrate that increased caloric intake isn't just a problem during the holidays. It also happens on most weekends.
"We thought weekends would present a problem for some people attempting to lose weight, but the consistency of our finding before and during the interventions was surprising," says first author Susan B. Racette, Ph.D., assistant professor of physical therapy and of medicine. "Subjects in the diet group lost weight during the week, but over the weekend, they stopped losing weight because they were eating more."
Racette's team followed 48 adults between the ages of 50 and 60 who took part in the CALERIE (Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy) study. Body mass index (BMI) ranked subjects as overweight or healthy weight when the study began. None were classified as obese.
Following earlier studies demonstrating that mice and rats live longer, healthier lives when on a calorie restricted diet, the CALERIE study is designed to determine whether taking in fewer calories over a long time period will slow down or reverse some of the common markers of aging and disease.
"But rats don't have weekends the way people do," Racette says. "On weekends, human lifestyle patterns can be very different. People have social events, parties to attend, and if they have children who play sports, they might be at fields all day long, relying on concession stands for food."
Study participants were divided into three groups: the first lowered their daily calorie intake by 20 percent, a second increased daily physical activity by 20 percent, and a third, control group did not change diet or activity levels. All three groups were monitored for one year. They kept food diaries, tracked exercise with accelerometers and were weighed regularly. Racette says people in the study didn't always realize they were eating significantly more food on weekends.
"It was surprising how consistent the findings were," she says. "We also were surprised by the dramatic way in which weekends continued to slow weight loss throughout the course of the study."
Before the interventions began, the researchers established "baselines" for each study participant's exercise and eating habits. This pre-intervention data determined that participants consumed the most calories on Saturdays. An average of 36 percent of their total calories came from fat on Saturdays, but less than 35 percent came from fat during the rest of the week. The typical weekend weight gain before the diet and exercise interventions began would have led to an average increase of 9 pounds a year.
When study participants were asked either to cut calories by 20 percent or to increase activity by a like amount, the pattern remained the same. Those in the calorie restriction group took in more energy on Saturday. Those in the exercise group ate more on both Saturday and Sunday. As a result, people in the calorie restriction group stopped losing weight on weekends, and those in the exercise group actually gained weight on weekends.
"People on diets often don't lose as much weight as we would expect, and this finding helps to explain why," she says.
As the researchers move into the second phase of the CALERIE study, looking at more subjects over a longer period of time, they now recommend that participants weigh themselves daily in order to be more aware of their patterns of weight loss and weight gain, particularly on weekends. For those not in a research study, she recommends moderation and careful planning to avoid weekend pitfalls.
"Planning ahead can't be emphasized enough," Racette says. She recommends packing healthy food if you're running errands, eating a little something so you aren't starving when you arrive at a party, even packing a light lunch before going to the kids' ballgames so that you have a choice other than junk food at a concession stand.
"In addition, she says, "paying closer attention to portion sizes can enable a person to enjoy the weekend without sabotaging weight-control efforts."

---

Racette SB, Weiss EP, Schechtman KB, Steger-May K, Villareal DT, Obert KA, Holloszy JO, and the Washington University School of Medicine CALERIE Team. Influence of weekend lifestyle patterns on body weight. Obesity, advance online publication doi: 10.1038/oby.2008.320
This study was supported by the National Institutes of Health.

Tags: Weight Control, weight loss,

Weight Loss Through Big Breakfast Diat, Is It For You?

Researchers have found a possible way to overcome the common problem of dieters eventually abandoning their diet and regaining the weight they lost. Eat a big breakfast packed with carbohydrates ("carbs") and protein, then follow a low-carb, low-calorie diet the rest of the day, the authors of a new study recommend. Results were presented Tuesday, June 17, at The Endocrine Society's 90th Annual Meeting in San Francisco.

"Most weight loss studies have determined that a very low carbohydrate diet is not a good method to reduce weight," said lead author Daniela Jakubowicz, MD, of the Hospital de Clinicas, Caracas, Venzezuela. "It exacerbates the craving for carbohydrates and slows metabolism. As a result, after a short period of weight loss, there is a quick return to obesity."

Only five percent of carbohydrate-restrictive diets are successful after two years, Jakubowicz said. Most carbohydrate-restrictive diets, she said, do not address addictive eating impulses.

With scientists from Virginia Commonwealth University in Richmond, Jakubowicz and her colleagues conducted a study, which they said shows that a diet's long-term effectiveness depends on its ability to increase a sense of fullness and bring down carb cravings. They compared their new diet with a strict low-carb diet in 94 obese, physically inactive women. Both diets were low in fat and total calories but differed in the carbohydrate distribution.

Forty-six women were on the very-low-carb diet, which allowed them to eat 1,085 calories a day. The diet consisted of 17 grams of carbohydrates, 51 grams of protein and 78 grams of fat a day. The smallest meal was breakfast, at 290 calories. For breakfast the dieters were permitted only 7 grams of carbohydrates, such as bread, fruit, cereal and milk. Dieters could eat just 12 grams of protein, such as meat and eggs, in the morning.

On the modified low-carb diet, or "big-breakfast diet," the other 48 dieters ate 1,240 calories a day. Although lower in total fat (46 grams) than the other diet, the new diet had higher daily allotments of carbs (97 grams) and protein (93 grams). Dieters ate a 610-calorie big breakfast, consisting of 58 grams of carbs, 47 grams of protein and 22 fat grams. The diet schedule for lunch was 395 calories (34, 28 and 13 grams of carbs, protein and fat, respectively); dinner was 235 calories (5, 18 and 26 grams, respectively).

The first half of the eight-month study focused on weight loss, and the last four months on weight maintenance. At four months, the women on the strict low-carb diet dropped an average of about 28 pounds, and the women on the big-breakfast diet lost nearly 23 pounds on average, which according to Jakubowicz was not significantly different. But at 8 months, the low-carb dieters regained an average of 18 pounds, while the big-breakfast group continued to lose weight, shedding another 16.5 pounds. Those on the new diet lost more than 21 percent of their body weight, compared with just 4.5 percent for the low-carb group. Furthermore, the study found that women who ate a big breakfast reported feeling less hungry, especially before lunch, and having fewer cravings for carbs than the other women did.

Jakubowicz said the big-breakfast diet works because it controls appetite and cravings for sweets and starches. It also is healthier than an extremely low-carbohydrate diet, according to Jakubowicz, because it allows people to eat more fruit and therefore get enough fiber and vitamins. She said she has successfully used the diet in her patients for more than 15 years.

Tags: Weight Control, weight loss, big-breakfast diet, Daniela Jakubowicz

The enzyme, CaMKK2, tone down appetite and promote weight loss, while improving the body’s ability to handle blood sugar levels.

Looks like controlling weight is going to be as easy as blocking an enzyme in brain at least in mice, for now. The enzyme, CaMKK2, able to tone down appetite and promote weight loss, while improving the body’s ability to handle blood sugar levels.
Following is the press release from Duke University Medical Center;
Contact: Mary Jane Gore
mary.gore@duke.edu
919-660-1309
Duke University Medical Center

Blocked brain enzyme decreases appetite and promotes weight loss

DURHAM, N.C. – Imagine being able to tone down appetite and promote weight loss, while improving the body’s ability to handle blood sugar levels.

That’s just what Tony Means, PhD, and his team at the Duke University Medical Center were able to do when they blocked a brain enzyme, CaMKK2, in mice.

“We believe we have identified an important drug development target that could potentially turn into a metabolic triple play: appetite control, weight loss and blood sugar management,“ said Means, who is the Nanaline H. Duke Professor and Chairman of Pharmacology and Cancer Biology.

For many years, scientists have been identifying and testing every step of the appetite stimulation and suppression pathways in search of a target. Such research is considered critical to finding ways for people to better control their weight and minimize their risk of developing diabetes, heart disease and other health conditions.

Activation of the enzyme CaMKK2 is just one step in the appetite stimulation pathway located in the hypothalamus section of the brain. An empty stomach releases the hormone ghrelin, which launches a cascade of signals that ultimately results in increased appetite.

Means and colleagues believed that CaMKK2 in the ghrelin pathway might be a likely candidate for study, because it activates AMPK, an enzyme that stimulates animals to eat and gain weight. They tested their theory in several ways, the results of which are published in the May issue of Cell Metabolism. The work was funded by NIH grants, as well as by the Australian Research Council, National Heart Foundation, and the National Health and Medical Research Council of Australia.

First they blocked CaMKK2 in mice with a specialized molecule inhibitor and then measured food intake. These mice ate significantly less food than untreated mice during the six days in which they were evaluated, and also lost body weight, which led the scientists to think they might be on to something.

Next they studied a group of mice that normally do not make CaMKK2 and found that the molecule inhibitor did not change feeding behavior or reduce weight. “The fact that blocking CaMKK2 worked in normal mice to make them eat less and lose weight, but not in mice missing the enzyme, provides compelling evidence that CaMKK2 signaling is a requirement for appetite control,” Means said.

They also studied both normal mice and mice missing CaMKK2 to learn how these types responded to low-fat and high-fat diets. After nearly 30 weeks on the specific diets, the normal mice on the high-fat diet became diabetic – they were unable to respond to insulin and weren’t able to manage blood sugar levels well. In contrast, the normal mice on a low-fat diet stayed healthy.

In mice missing CaMKK2, the scientists found that they stayed healthy regardless of whether they were on a low-fat or high-fat diet. The CAMKK2-negative mice apparently were protected from changes that lead to diabetes in a high-fat diet.

“Remarkably, we find that blocking CaMKK2 in the brain prevents the deposits of fat in liver and skeletal muscle that are characteristic of obese, diabetic patients,” Means said. “We find this very exciting and are trying to understand the mechanism responsible for this protective effect, as well as to identify more potent drugs to inhibit CaMKK2.”

Tags: weight loss, blood sugar level, CaMKK2enzyme, Duke University Medical Center